A comparable positioning system is known from the DE-OS No. 30 24 109.
The system therein described has a single valve stem, one end of which is connected to the valve disk of an internal combustion engine, while the other end carries an anchor plate capable of reciprocating travel between two solenoids. An adjusting solenoid is provided to guide the locus of equilibrium of the spring system to an operational position upon startup, and to achieve this a support forming the seat of the spring system must be shifted. Insofar as the stem is also guided by the support, it is important that no tilting take place during support movement, so that, when the support has arrived at its operating position, stem guidance is as friction-free as possible.
However, in the normal operating RPM range of modern engines, the valve actuators must change positions frequently, at precise intervals, and their stroke must be the full length of intended travel. At the high temperatures and frequency of movement, friction due to even slight misalignment of tappets and/or actuators can delay properly timed valve opening and closing, reduce opening, or hinder complete closing, thereby causing reduced engine performance. There is thus a significant need for improved valve actuator guide and centering mechanisms.